Cops finish 'final sweep' of missing Calgary family's home

A candle memorial is set up in front of the home as Calgary city police sift through articles in the garage on Saturday July 12, 2014 of the home where five-year-old Nathan O'Brien and his grandparents Alvin and Kathryn Liknes went missing in Parkhill in SW Calgary, Alta. Stuart Dryden/Calgary Sun/QMI Agency

CALGARY -- Investigators have pulled out of the original scene at the centre of the mysterious disappearance of a Calgary family.

Police returned to the Parkhill home of Alvin and Kathryn Liknes Saturday to complete a "final sweep" of the property and ensure they hadn't missed any clues in previous searches.

The Likneses, along with their five-year-old grandson Nathan O'Brien who had spent the night June 29, were reported missing the morning of June 30 by Nathan's mom when there was no one at the home when she went to fetch her son about 10 a.m.

An Amber Alert was issued that day.

Police later said a violent incident had taken place at the home.

On Sunday, after holding the property for nearly two weeks, police announced the Liknes home had been released from continuity.

Meanwhile, investigators continued to comb through trash at the Spyhill landfill and, along with RCMP resources, scoured an Airdrie, Alta., acreage and the surrounding area.

Police were led to the acreage through a tip and found a green Ford truck matching the description of one spotted in Parkhill the night of the family's disappearance.

They also took a man they have been referring to as a person of interest, Douglas Garland, in for questioning. He was not charged in relation to the case, but did appear in court last week on unrelated charges.